[A case of acute osteomyelitis and subperiosteal abscess caused by Streptococcus pyogenes, presumably triggered by influenza A virus].

A feverish 5-year-old girl diagnosed with influenza A virus from a positive rapid influenza type A antigen test, and suffering pain and redness in her left knee had febrile convulsions and was admitted. Her knee pain and redness increased. She was diagnosed with acute osteomyelitis and subperiosteal abscess based on MRI. We started intravenous antibiotics and punctured and drained the abscess. S. pyogenes was isolated from blood and puncture pus culture and a rapid group A beta hemolytic Streptococcal antigen test was positive in a throat swab. After 10 days' drainage and 28 days' antibiotics treatment, she was discharged. Viral superinfections aggravate S. pyogenes infection both in animal models and human cases. This case gives futher evidence that superinfectious influenza A virus is a risk factor for severe S. pyogenes infection.